can a 20 mm gallstone be expelled out of gallbladder?

hi, i was dignosed with kidney and gallstone two years ago.
the doctors asked me to not worry about the gallstone much.

two years ago the gallstone was 14 mm but now its 20 mm and is easily seen in simple X-ray(KUK) and ultrasound.
it is completely silent stone(its free floating). i rarely get a feeling of like some air trapped in that region(very rare).
doc suggested to remove gallbladder, but i wont after reading some consequences.

BUT MY ONLY WORRY IS THAT THE STONE IS 20 MM IN SIZE AND DOUBT THAT IT MAY GET STUCK IN THE DUCT, WHICH IS AGAIN A PROBLEM( I THINK A BIG PROBLEM). HAS ANY PASSED SUCH A BIG STONE WITH FLUSH AND CONFIRMED THE RESULT WITH ULTRASOUND?

CAN ANY ONE ASSURE ME THAT ANY OF THE FLUSHES MENTIONED ON THE SITE WILL EXPEL SUCH BIG STONE. I HAVE NEVER DONE ANY FLUSH BEFORE. CAN ANYONE SUGGEST ME THE BEST ONE.

AND ONE NOTE FOR ALL THOSE WHO THINK THAT THOSE HUNDREDS OF STONES PASSED AFTER THE FLUSH ARE ACTUAL STONES THEN LOOK AT THE COMMENTS IN THIS ARTICLE
://www.curezone.org/cleanse/liver/huldas_recipe.asp

I WANT MY REAL STONE ( RESIDING IN GALLBLADDER) TO BE EXPELLED , NOT JUST THE ONES THAT ARE FORMED AT NIGHT DURING THE FLUSH.